The effect of architectural theories on everyday practice is hard to pin down. On one hand, Vitruvius’s holy trinity of firmness, commodity, and delight are foundational to why architecture matters in the largest sense. On the other hand, his theoretical trinity is a little inscrutable when it comes to change orders or building codes.

Nevertheless, the most powerful theories—from Vitruvius to Venturi—have connected architecture’s purpose to provide shelter with its potential to inspire its inhabitants. It may surprise you to learn that the General Services Administration (GSA) has operated since 1962 according to its own homegrown architectural theory: the “Guiding Principles for Federal Architecture.” Fifty years later, these principles have forged stronger links between theory and practice than other architectural philosophies, which too often perpetuate the enormous gap. More importantly, these principles still guide some of this country’s most adventurous works of public architecture.

In 1949, President Truman created the GSA, which assumed the authority to commission and construct federal buildings from the Treasury Department. But, by 1959, the government had not kept pace with its own internal growth. President Kennedy formed a committee on federal office space to investigate how to expand inside (and beyond) the Beltway as well as tackle critiques of banal federal architecture. Daniel Patrick Moynihan (who later became a senator from New York) chaired the committee, and the rest is, well, history. In what was a simple report on the narrow question of office availability, Moynihan declared a broad architectural theory that he humbly titled “Guiding Principles for Federal Architecture.” He did it in just over 500 words.

“There’s a pragmatic side of theory,” says Julie Snow, FAIA, whose firm, Julie Snow Architects, has worked on several projects with the GSA. “And, for me, that doesn’t exclude the aspirational side of Moynihan’s comments—the idea that architecture has the ability to reflect the aspirational side of democratic life and culture.”

Written in the spirit of urbane optimism, the “Guiding Principles” established public architecture’s functional and symbolic roles. Moynihan references the Vitruvian need for firmness and commodity, and then calls for delight by stating that design “must provide visual testimony to the dignity, enterprise, vigor, and stability of the American Government.” All told, it is much more than a call for “good design”; it is a call for smart design that is economic, contemporary, contextual, and accessible. By connecting public building and our national character, Moynihan’s words became the architectural conscience of the federal government by couching architecture as the art of building rather than merely a design service. “Major emphasis should be placed on the choice of designs that embody the finest contemporary American architectural thought,” writes Moynihan, pointing out that this emphasis must “flow from the architectural profession to the Government, and not vice versa.”

“Amongst architects, the GSA is looked upon as a great client—not least because they are seen as being at the forefront of how architecture and social space can be developed,” Snow says. “I’ve actually started lectures by telling people to go read the Moynihan principles because he articulates what architects do—and should do.”

At mid-century, when Beaux-Arts Classicism dominated public buildings in Washington, D.C., and elsewhere, American designers were also building boldly for the future in structures such as Washington’s Dulles International Airport, completed in 1962 and designed by Eero Saarinen, FAIA. Moynihan, for his part, did not mandate traditionalism, or flinch from placing the responsibility for “delight” on the shoulders of the architect—a remarkable commitment to art as well as an abdication of control.

Congress approved the Brooks Act in 1972, which allows the federal government to commission architecture firms through a two-tier procurement process, rather than limiting itself to the lowest bidder. In 1973, the GSA reinstated the Art in Architecture Program, which mandates a percentage of construction costs for art and emphasizes careful coordination between building and artistic design. In 1994, the GSA initiated its Design Excellence Program, which commissions leading architects and relies on a wide group of private-sector peer reviewers to comment upon both new design and the restoration or renovation of existing structures. Moynihan’s principles, written at a time of perceived dullness in federal design, served as the theoretical basis for the Design Excellence Program, founded to reinvigorate the GSA’s architectural inventory.

Over the past 50 years, Moynihan’s “Guiding Principles” have been interpreted to accommodate the most pressing design concerns of the age. In the first few decades, structures such as the Robert C. Weaver Federal Building in Washington, D.C. (the headquarters of the U.S. Department of Housing and Urban Development, completed in 1968 and designed by Marcel Breuer, FAIA), and Chicago’s Kluczynski Federal Building (completed in 1974 and designed by Ludwig Mies van der Rohe, FAIA), blended efficient corporate Modernism with a call for distinctive public spaces.

As architectural trends shifted, the “design freedom” edict of Moynihan’s principles allowed it to adapt. The Juliette Gordon Low Federal Building in Savannah, Ga., completed in 1986, fits snugly into one of the city’s historic squares through the use of appropriate scale, even if its exterior subway-tile cladding has been called a misstep by architectural critics. In addition, the restoration of the Jose V. Toledo Federal Building and U.S. Courthouse in San Juan, Puerto Rico, in 2002 by Maurice Finegold, FAIA, is an excellent example of regionalism, historic preservation, and adaptive use—three important tenets of sustainability. More recently, passive heating and cooling has become another important tenet of sustainability, inspired, in part, by historic structures and enabled by evolving technologies. The poster child of this movement among recent GSA buildings is the San Francisco Federal Building, completed in 2007 and designed by Thom Mayne, FAIA, principal of the Los Angeles firm Morphosis. Not only did Mayne’s team advance passive systems by showing that they could be used on a large scale, but the team integrated high-security measures in the process.

Moynihan did not intend for his white paper to evolve into a theory; but, as the GSA has continued to execute his vision and adapt to changing trends, the “Guiding Principles” have become a coherent set of tested propositions. The evidence speaks for itself.

On May 16, the GSA will host the Moynihan Symposium on Public Design in Washington, D.C., which is free and open to the public, in conjunction with AIA National Convention. To register, visit convention.aia.org; to read more about the buildings discussed here, visit aia.org.